It has been clearly established that women's saliva during her menstrual cycles can be used to determine their fertile period. Scientists have observed a clear difference in the cell pattern in saliva between fertile and sterile periods. More particularly, scientists have found that during a woman's fertile period, a sample of dried saliva forms vein-like structure or fern leaf like pattern. Contrary to the above, during sterile periods, the dried saliva sample typically forms a spotted or a dot like pattern.
In order to administer self-examination, special optical devices such as microscopes or magnifying glasses are available in the market.
U.S. Pat. Nos. 4,815,835 and 5,267,087 which are incorporated herein as reference describe such handy ovulation tester devices. The handy ovulation testers prepared in accordance with the teachings of the aforesaid documents and those existing in the market have certain shortcomings such as the lack of clarity of the image. The clarity of the image apparent to the user is very much wanting at times, so the user often lacks some degree of confidence in her observation. In order to obviate such shortcomings, efforts have been made in the present invention to improve the clarity of image by certain built-in quality and optical design features, which are simple and do not change their form or cost materially.
In erstwhile ovulation testers, the eyepiece needs to be focused by screwing or pushing the eye piece lens part, which is usually called an outer part with respect to an inner part to see or magnify the object (biological specimen such as dried saliva) clearly. This approach of focusing is cumbersome from the point of view of users who will have to be made aware of this technique before use. This approach often causes some strain to the eye besides manual effort.
Constructionally, the prior art devices comprise of inner and an outer telescopic tubes which are configured to move in and out with respect to each other. The eyepiece is incorporated at the top end of one of the telescopic tubes (preferably the inner tube) and the other telescopic tube (preferably the outer telescopic tube) is provided with a provision to accommodate a slide having the biological specimen thereupon. A light source is located opposite to the end having the eyepiece so as to illuminate the biological specimen. The light source can be a bulb or LED. The inner and the outer tubes are moved with respect to each other in order to achieve focusing on the slide having the biological specimen. Due to the telescopic construction of the tubes, the eye piece and the object (the biological specimen) are aligned in different planes for focus and hence the probability of error/unclear image increases for want of coaxiality in lens and surface of object.
In existing focusable devices, one tube containing lenses and the other one containing object surface are either pushed or turned against each other, thus creating the focusing effect. However as the time passes, the areas that are pushed or rotated get worn out causing difficulty to accurately adjust the focus of the device. Also, it is observed that by the action of pushing or rotating the telescopic tubes, dust particles generated due to the rubbing action of the moving parts fall on the enclosed optical surface and onto the opposite surface of the glass plate wherein the biological specimen is applied. Settlement of these dust particles causes spurious shadows on the image and adversely affects the contrast and sometimes confuses the user.
Further due to the two-piece construction, the inventors have very often observed that the moisture from the environment and even very fine dust particles enters into the eyepiece and hamper the quality of the image.
Even when we look into manufacturing a set of telescopic tubes which are accurately co-axial and which do not have minimum gap between them, it can be a complex task. To avoid misalignment of the telescopic tubes, special materials are required to be provided between them.
Further, looking into the cost of such a telescopic device, due to the complexity in the manufacturing process of these devices and the amount of special devices to be used for obtaining the alignment of the telescopic tubes, the cost of manufacturing is substantially high.
Thus, there appears a necessity to develop an improved and handy portable microscope apparatus for viewing biological specimens such as saliva for the detection of woman's fertility period during her menstrual cycle, having fixed focus that overcomes the disadvantages discussed above.